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54 Alexandra (A858 RA)
Classification: Main-belt Asteroid          SPK-ID: 2000054
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbit Diagram
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Note: This Java-based orbit viewer will eventually be retired.

Note: Make sure you have Java enabled on your browser to see the applet. This applet is provided as a 3D orbit visualization tool. The applet was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances. For accurate long-term ephemerides, please instead use our Horizons system.

Note: If the applet is not working, here are some notes that might help.
Orbit Viewer

Additional Notes: the orbits shown in the applet are color coded. The planets are white lines, and the asteroid/comet is a blue line. The bright white line indicates the portion of the orbit that is above the ecliptic plane, and the darker portion is below the ecliptic plane. Likewise for the asteroid/comet orbit, the light blue indicates the portion above the ecliptic plane, and the dark blue the portion below the ecliptic plane.

Orbit Viewer applet originally written and kindly provided by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 169 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1973025749458085 3.6079e-08  
a 2.711027960126701 6.5422e-09 au
q 2.17613516284362 9.8474e-08 au
i 11.79820862777852 4.1809e-06 deg
node 313.2467645619165 1.7869e-05 deg
peri 345.0504794117631 2.0191e-05 deg
M 106.6242659964101 1.0985e-05 deg
tp 2458517.604703134470
4.903e-05 TDB
period 1630.419729008441
n .2208020386375833 7.9925e-10 deg/d
Q 3.245920757409781 7.833e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2530  
   data-arc span      57082 days (156.28 yr)  
   first obs. used      1863-10-24  
   last obs. used      2020-02-05  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .463  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Feb-22 15:15:48  

Additional Information
 Earth MOID = 1.16282 au 
 Jupiter MOID = 2.01438 au 
 T_jup = 3.305 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 7.8   n/a MPO492748 IRAS observations used: 14
diameter diameter 160.120 km 1.857 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
rotation period rot_per 7.024 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List:
[Van Houten-Groeneveld, I.; van Houten, C.J.; Zappala, V. (1979) Astron. Astrophys. Suppl. Ser. 35, 223-232.]
[Di Martino, M.; Zappala, V.; De Sanctis, G.; Cacciatori, S. (1987) Icarus 69, 338-353.]
[Bel'skaya, I.N.; Dovgopol, A.N.; Erikson, A.; Lagerkvist, C.-I.; Oja, T. (1993) Astron. Astrophys. Suppl. Ser. 101, 507-511.]
[Behrend, R. (2005) Observatoire de Geneve web site,]
[Torppa, J.; Hentunen, V.-P.; Paakkonen, P.; Kehusmaa, P.; Muinonen, K. (2008) Icarus 198, 91-107.]
[Warner, B.D.; Durech, J.; Faurerbach, M.; Marks, S. (2008) Minor Planet Bull. 35, 167-171.]
[Higgins, D.; Warner, B.D. (2009) Minor Planet Bull. 36, 159-160.]
[Durech, J.; Kaasalainen, M.; Herald, D.; Dunham, D.; et al. (2011) Icarus 214, 652-670.]
[Durech, J. (2011) Database of Asteroid Models from Inversion Techniques (DAMIT).]
[Hanus, J.; Marchis, F.; Durech, J. (2013) Icarus 226, 1045-1057.]
[Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.]
[Hanus, J.; Viikinkoski, M.; Marchis, F.; Durech, J.; et al (2017) Astron. Astrophys. 601, A114.]
geometric albedo albedo 0.059   0.014 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
B-V BV 0.727   0.027 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=9; phase (min.=4.77, mean=11.55, max.=25.49) deg.
U-B UB 0.357   0.037 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=7; phase (min.=4.77, mean=11.92, max.=25.49) deg.
Tholen spectral type spec_T C   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B C   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)

54 Alexandra (A858 RA)          Discovered 1858-Sep-10 by Goldschmidt, H. at Paris
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ hide close-approach data ]
Close-Approach Data   ...sorted by Date/Time (TDB)
Date/Time (TDB) Time Uncertainty
Body Nominal Distance (au) Minimum Distance (au) Maximum Distance (au) V-relative (km/s) V-infinity (km/s) JD (TDB) Time Uncertainty (minutes) Semi-major axis (km) Semi-minor axis (km) range-LOV angle (deg) N-sigma BP Orbit Ref. Reference Modified
2132-Sep-21 12:34 00:01 Jupiter 1.99688676162282 1.99688644449639 1.99688707875027 3.46063622245122 3.33581474324371 2500021.023399529 1.2861440390473 190.511682148907 11.2588051131598 -86.8599655164698 3758845.34169702 T 169 CATAB v2.0f-lin.ifort 2020-Feb-22 15:16:02 2020-Feb-22 15:16
2168-Jul-01 22:45 00:02 Jupiter 1.99401840069531 1.99401807280296 1.99401872858767 3.54097487748644 3.41890913791087 2513088.447919599 1.66863692658942 234.077920195542 14.0830131249374 -89.0780748632086 3848295.31089318 T 169 CATAB v2.0f-lin.ifort 2020-Feb-22 15:16:02 2020-Feb-22 15:16

Alternate Designations
 A858 RA = 1950 BT = 1974 HG1 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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